Tone-arm for phonographs.



R. H. CONE, JR. TONE ARM FOR PHONOGRAPHS.

APPLKJATION FILED JUNE 29. 1916.

Patented Apla 23, 1918.

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RoRRR'r H. coma, JR, or sun. LOUIS, MISSOURI.

TONE-ARM FOR'PHCIDNOGRAPHS.

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Specification of Letters Patent.

Patented Apr. 23, 191..

Application filed June 29,1916. Serial No. 106,557.

To all whom it may concern:

Be it known that l[, ROBERT H. Conn, Jr., a citizen ofthe United States, and a resident of the city of St. Louis and State of Missouri, have invented a new and useful Improvement in Tone-Arms for Phonographs, of which the following is a specification,

This invention relates. to phonographs of the disk type, and its object is to enable both records having vertical undulations and those having transverse undulations to be played by the same instrument.

The invention consists in an arrangement of sound box and tone arm, and a joint connection between the sound box and the tone arm for enabling the sound box to beset in either of two positions at right angles to each other. The invention further consists in a joint connection between the sound box and tone arm permitting the sound box to be turned up ofl of the record and out of the way. The invention also consists in a joint connection for holding securely the sound box in either of two positions of adjustment, and which permits changing from one position to the other by merely twisting the sound box with the hand. 7

Further details of the invention and what it consists in appear in connection with the device shown in the drawings, as hereinafter described and claimed.

][n the drawings, wherein the same reference characters designate the same parts in the several views,

Figure 1 is a side elevation of a tone arm and sound box embodying the invention, showing the sound box in position for playing records having vertical undulations;

Fig. 2 is a longitudinal section of the same in a vertical plane through the axis of the tone arm;

Fig. 3 is a cross-section on the tone arm on the line 33 in Fig. 2; and

Fig. 4 is a cross-section of the elbow porgon of the tone arm, on the line 4.4: in ig. 2.

The sound box is shown in dot and dash lines in Fig. 1 in position for playing records having lateral undulations; and it is also shown in dot and dash lines in Fig. 1 thrown up away from the record.

The tone arm 10 is mounted at one end (not shown) for both horizontal and vertical swinging movement whereby its other end, which supports the sound box 11 and stylus (not shown), is free to move to permit the stylus to be supported in and'to follow the groove of the record. The axis AB of the tone arm is'normally horizontal (as shown in Fig. 1), and the vertical swinging movement of the arm is slight and is restricted by suitable stops (not shown) which maintain the arm substantially horizontal when the sound box is turned up andthe.

stylus is oil of the record.

The free end of the tone arm has an elbow 12, one branch of which has a reduced extension 13 which isrotatably secured within the end of the tone arm, and the other branch of which normally projects down at an angle of about sixty degrees to the horizontal, on the axis BC in Fig. 1. The sound box has a hollow .stem 14 which makes a right "angle turn at the back of the sound box and its end 15 is, reduced and is rotatably secured within theangularly projecting branch of the elbow 12. By this arrang'ementf the axis CD of the sound box makes an angle of about thirty degrees with the horizontal in the position shown in full lines in Fig. l, and the sound box may be turned on the axis BC of the stem until the axis CD is parallel to the horizontal, as shown at 11' in dot and dash lines in Fig. 1. The sound box may also be turned up to lift the stylus off of the record by swinging the elbow 12 around on the horizontal axis AB, as shown at 11? in dot and dash lines in Fig. 1.

The end 13 of the elbow 12 is held in adjusted position in the end of the tone arm by means of a detent pin 16 which is. slidably arranged in a transverse hole through the end of the elbow with one end projecting from the hole and engaging in a circumfercntial groove 17 in the inner wall of the tone arm. The pin 16 is yieldingly held in place with its point in the groove by means of a small spring 18. The groove 17 extends around the inside of the tone arm throu h an angle of about one-hundred and fi ty degrees, and terminates at each end in depressions 19 for the point of the pin to catch in. The depressions 19 at the ends of the groove 17 are so located as to hold the elbow secured in either of its desired positions. The sides of the depressions 19 are slanting so the pin 16 can slide out and the elbow may be turned from one position'to the other without difficulty.

The end 15 of the stem 14 of the sound box is held in adjusted position in the end of the elbow by a detent 21 which is slidably arranged in a transverse hole through the end of the stem withone end projecting from thehole and engaging in a circumferential groove 22 in the inner wall of the elbow. The pin 21 is yieldingly held in place with its point in the groove by means of a small spring 23. The groove 22 extends around the inside of the elbow through an angle of ninety degrees, and terminates at each end in depressions 24 for the point of the pin to catch in. The depressions 24 are so located as to hold the sound box securely in either of its two positions of adjustment, and the shape of the depressions is such that the sound box may be turned from one adjusted position to the other atlright angles thereto without difliculty. A rubber washer 25'is inserted between the end of the elbow and the shoulder at the junction of the end 15 and the stem of the sound box. Moreover, the sound box may be removed by merely pulling its stem out of the end of the sleeve, the. pin 20 having suflicient movement to permit it to be pressed into its hole out of engagement with the groove 21. Likewise, the elbow 11 ma be removed from the tone arm 10 by mere y pulling it out.

The joints between the tone arm, the elbow, and the sound box are smooth and neat looking on the outside and the obstruction which they constitute to the transmission of sound within the tone arm is slight. The construction also permits the sound box and stem to be cast in one piece, thereby reducing liability of vibration from looseness of the parts. The invention is not restricted to the precise details of construction shown and described.

' I claim the following as my invention:

1. A tone arm for a phonograph having an elbow at its free end, said elbow having an extension projecting into the end of the tone arm, a circumferential groove on the inside of the tone arm outside of and partly encircling said extension, a depression at each end of said groove, said extension having alining transverse holes in its opposite walls, and a pin slidably mounted in said transverse holes and guided in both walls of said extension and having one end project ing therefrom and resilient means for engaging said pin in one or the other of said epressions, thereby holding said elbow in its corresponding angular position.

2. A tone arm for a phonograph having an elbow at its free end, said elbow having an extension projecting into the end of the tone arm, a circumferential groove on the inside of the tone arm outside of and partly encircling said extension, said extension having alining transverse holes in its opposite walls and a pin slidably mounted in said transverse holes and guided in both walls of said extension, and having one end projecting therefrom and engaging in said groove, and a spring pressing the end of said pin in said groove to .hold said elbow in position.

3. A tone arm for a phonograph having a sound box loosely arranged upon its free end, said sound box having an extension projecting into theend of the tone arm, a circumferential groove on the inside of the tone arm outside of and partly encircling said extension, and a pin slidably mounted at its ends in a transverse hole in said extension and having one end projecting therefrom and engaging in said groove, the

Walls of said groove being inclined and said pin having a tapered point adapted to seat in said groove to hold said sound box in position, and a spring for releasably holding said pin in said groove whereby said sound box may be removed.

Signed at St. Louis, Missouri, this 27th day of June, 1916.

ROBERT H. CONE, JR. 

